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Band offset and interface chemistry of HfO 2 /Si (001) prepared by electron‐beam evaporation in ultrahigh vacuum using atomic oxygen
Author(s) -
Run Xu,
Minyan Tang,
Zhijun Yan,
Linjun Wang,
Yiben Xia,
Fei Xu
Publication year - 2011
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201046194
Subject(s) - silicon , electron beam physical vapor deposition , analytical chemistry (journal) , chemistry , synchrotron radiation , oxygen , band offset , electron , ultra high vacuum , atomic physics , materials science , chemical vapor deposition , nanotechnology , optoelectronics , band gap , optics , valence band , physics , organic chemistry , chromatography , quantum mechanics
The band offset and interface chemistry of HfO 2 films prepared by ultrahigh‐vacuum electron‐beam evaporation was investigated by synchrotron radiation photon electron spectroscopy (SRPES). A relatively large valence band (VB) offset of the HfO 2 film with Si was determined to be 3.56 eV. Both the Hf‐silicate and a small number of HfSi bonds were formed at the interface of HfO 2 /Si. This HfSi bond, which cannot be prevented completely in an ultrahigh‐vacuum preparation system using the Hf metallic source despite the atomic oxygen source adopted, may be mainly responsible for this large value of VB offset of HfO 2 /Si(001). This result also suggests that metal–silicon bonds at the interface of high k oxides on Si may generally lead to a larger VB offset than that with all silicon atoms at the interface bonding directly with oxygen.